The end face of a cylinder-piston unit has a press-in area, engaging around the mouth, and a press-on area, surrounding the press-in area. The press-in area comprises an inner web, delimiting the mouth, and an outer web. The webs delimit a recess, which surrounds the inner web and of which the depth measured parallel to the center axis of the cylinder-piston unit is at least a quarter of its width in a plane oriented normal thereto. The press-on area, at least during an injection, is offset counter to the injection direction relative to the end face of the press-in area. Moreover, the surface of the press-on area projected into a plane normal to the center axis is at least as large as the surface of the press-in area projected into the same plane.
